发表机构
National Central University; Max Planck Institute for Extraterrestrial Physics; University College Dublin; Kyoto University; Space Telescope Science Institute; Henan Academy of Sciences（中央大学; 马克斯·普朗克地外物理研究所; 都柏林大学学院; 京都大学; 空间望远镜科学研究所; 河南省科学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
对超亮超新星SN 2018bsz的多波段测光分析发现其峰值后光变曲线存在约31.6天的准周期调制，可能源于中心引擎进动或与星周物质相互作用。
AI 中文摘要
超新星（SN）光变曲线中的重复结构可能揭示与中心引擎动力学、双星轨道运动或与结构化星周物质（CSM）相互作用相关的物理时钟。我们利用Swift/UVOT和GROND的观测数据，对邻近的贫氢超亮超新星（SLSN-I）2018bsz（z=0.0267）进行了多波段测光再分析，观测覆盖了最大光度后约110个静止帧天。在独立建模并扣除每个波段的平滑衰减后，广义Lomb-Scargle周期图在从u到Ks的十个波段中揭示了相位大致一致的重复残差变化。最强的单波段探测出现在g、r、i、z和J波段，得到的周期为31.5-31.8天，而联合多波段分析给出的静止帧周期为P=31.61（±0.03）天。该调制被追踪了约三个周期，因此被描述为准周期。该信号对采用的去趋势方法具有稳健性，而比较星和月相周期测试则排除了观测系统效应。该调制从光学到近红外波段大致相位相干，但其振幅向较短波长方向增加；显著性较低的波段也显示出最佳拟合周期可能存在波长依赖的偏移。目前的观测无法唯一确定其物理起源。Lense-Thirring进动、与爆炸前形成的CSM相互作用以及爆炸后与幸存伴星的相互作用仍是可能机制。SN 2018bsz提供了SLSN-I中清晰的、月尺度相干测光调制的范例之一。
英文摘要
Recurrent structure in supernova (SN) light curves may reveal physical clocks associated with central-engine dynamics, binary orbital motion, or interaction with structured circumstellar material (CSM). We present a multiband photometric reanalysis of the nearby hydrogen-poor superluminous SN (SLSN-I) 2018bsz (z=0.0267), using Swift/UVOT and GROND observations spanning approximately 110 rest-frame days after maximum light. After independently modelling and subtracting the smooth decline in each band, Generalized Lomb-Scargle periodograms reveal recurrent residual variations at broadly consistent phases across ten bands from u to Ks. The strongest individual-band detections, in the g, r, i, z, and J bands, yield periods of 31.5-31.8 days, while the joint multiband analysis gives a rest-frame period of P=31.61 (+/-0.03) days. The modulation is traced over approximately three cycles and is therefore described as quasi-periodic. The signal is robust to the adopted detrending procedure, while comparison-star and lunar-cycle tests disfavour an observational systematic. The modulation is broadly phase-coherent from the optical to the near-infrared, but its amplitude increases towards shorter wavelengths; lower-significance bands also show possible wavelength-dependent shifts in the best-fitting period. The present observations do not uniquely determine the physical origin. Lense-Thirring precession, interaction with CSM structured before the explosion, and post-SN interaction with a surviving companion remain possible. SN 2018bsz provides one of the clearest examples of coherent, month-scale photometric modulation in an SLSN-I.
Comments14 pages, 9 figures
